An example of a known electrical connector construction is described in U.S. Pat. Nos. 4,907,983 and 5,115,563 (hereafter respectively "the '983 patent" and "the '563 patent"), which are incorporated herein by reference. FIG. 1 illustrates the components of this known electrical connector, which include an inner conductor 3, an outer conductor 5, and an insulator 7. The outer conductor 5 is provided with a central bore 9 that is defined in part by an inwardly directed substantially annular ridge 2 which defines the minimum diameter of the bore. The insulator 7 is provided with a substantially annular recess 6 along its outer surface. Additionally, the insulator also has a central bore 4 extending through its length,
A method of assembling the connector components is described in the '563 patent. Initially, the insulator 7 is inserted into the outer conductor bore 9 until the insulator recess 6 aligns with the annular ridge 2. When the insulator 7 is in an unstressed state, its maximum diameter is greater than the minimum diameter of the outer conductor bore 9. However, when passed through the annular ridge 2 during insertion, the insulator 7 is radially compressed to a smaller diameter. After the insulator 7 is positioned within the outer conductor, the inner conductor 3 is inserted into the insulator bore 4. The insertion of the inner conductor radially expands the insulator 7 and assists in moving it back to its unstressed configuration, and into solid engagement with the walls defining the outer conductor bore 9. Thus, the connector assumes its assembled configuration as shown in FIG. 2. The above described method of assembly is advantageous because it does not require the use of any additional binding materials or the application of heat.
As described in the '983 patent, the connector 1 is characterized by having an improved mechanically tight seal so that the inner conductor 3 and outer conductor 5 maintain a rigid mechanical interconnecting relationship over a wide temperature range. This advantage is obtained by the interlocking engagement between the annular ridge 2 of the outer conductor 5 and the insulator's annular recess 6.
Although the above-described connector has been found to work effectively in many applications, it does not include any means for preventing rotation of the inner conductor 3 relative to the insulator 7, or of the insulator relative to the outer conductor 5. Thus, this connector may not satisfy some military specifications which require that the connector withstand specified amounts of torque applied to its components without altering the relative rotational positions of the inner and outer conductors. For example, some military specifications for electrical connectors require that the device withstand the application of up to four ounce-inches of torque to the inner conductor 3. Furthermore, it is also desirable to prevent relative rotation of the connector components for connectors used on printed circuit (PC) boards. When a connector is used on a PC board, one end is typically soldered to a connection on the board, and an electrical component is screwed into a mating relationship with the free end of the connector. If the inner and outer conductors are free to rotate relative to each other, the action of screwing a component into the free end of the connector may cause the fixed end to rotate and break the solder connection.
Several techniques have been developed for preventing relative rotation between the components of an electrical connector. An example of such a technique uses an epoxy pin to engage each of the connector components. Initially, one or more holes are provided in the inner and outer conductors, as well as the insulator. An epoxy is injected into the holes to form a pin that engages each of the connector components and prevents them from rotating relative to one another. Although this technique is effective in preventing relative rotation, it has several disadvantages. First, electrical leakage tends to occur at the holes provided in the inner and outer conductors, thereby reducing the performance of the connector. Second, it is difficult to provide an epoxy pin that has a uniform configuration as it extends through the outer conductor, insulator, and inner conductor, and as a result, the electrical characteristics of the connector may vary depending on the exact configuration of the epoxy pin. Third, the epoxy is messy and may undesirably contaminate other electrical components, possibly interrupting proper electrical contact and requiring disassembly of the connector. Finally, this technique typically involves several time-consuming steps, including allowing the connector to sit for a long period of time so that the epoxy has ample time to set properly.
Accordingly, it is an object of the present invention to provide an improved electrical connector having an improved mechanism for preventing relative rotation of its components.